Crankshaft driven piston type molecular sieve oxygen generation system consists of four sets of piston cylinder oxygen generation devices A, B, C and D, each piston cylinder oxygen generation device includes piston, piston cylinder, crankshaft, connecting rod, silo, oxygen exhaust valve , intake valve and nitrogen exhaust valve; it is characterized in that: a piston is installed in the piston cylinder of each set of piston cylinder oxygen generator, the lower end of the piston cylinder is a silo, the upper layer of the silo is a filter layer, and the lower layer of the silo is Oxygen molecular sieve, the funnel-shaped bottom of the silo is connected with the oxygen exhaust valve; there is a piston head in the center of the top plane of the piston, the upper end of the piston head is connected with the connecting rod by the connecting shaft of the piston head and the connecting rod, and the upper end of the connecting rod is connected with the crankshaft by The crankshaft is connected to the connecting shaft of the connecting rod, and the crankshaft is connected to the transmission shaft, so that when the crankshaft rotates around the transmission shaft, it drives the connecting rod to move up and down and makes the upper end of the connecting rod swing back and forth around the connecting shaft between the piston head and the connecting rod, so that the piston moves on the piston. The cylinder moves up and down, and the composition and structure of the four sets of piston cylinder oxygen generators A, B, C and D are exactly the same.